Technical Field
The present disclosure relates to a print method, an ink set, and an inkjet print device.
Description of the Related Art
For industrial use in advertisement and signboards, for example, non-permeable recording media such as plastic film are used in order to improve durability for light, water, abrasion, resistance, etc. Naturally, inks for such non-permeable recording media have been developed.
As such inks, for example, solvent-based inks using organic solvents as solvents and ultraviolet-curable inks mainly constituted of polymerizable monomers have been widely used. However, the solvent ink causes a concern about an adverse impact on the environment due to evaporation of organic solvents. The ultraviolet curing ink has a limited choice of polymerizable monomers in terms of safety in some cases.
For this reason, ink sets including aqueous ink capable of direct recording on non-permeable recording media have been proposed.
Such non-permeable media are demanded particularly when white images are formed as backdrop on transparent film by an inkjet recording method to form printed matter thereon. As the inkjet recording method, there are a first recording method and a second print method. The first recording method includes forming a white image on a recording medium with a white ink (first recording process), drying the white image, and thereafter forming a non-white image on the white print layer with an ink including a non-white coloring material (second print process). The second print method includes forming a non-white print layer on a recording medium with an ink including a non-white coloring material (first print process), drying the non-white print layer, and thereafter forming a white print layer on the non-white print layer with a white ink (second print process).
As for the aqueous ink, for example, an inkjet recording method has been proposed which includes a first recording process of recording a white image on a recording medium with a white ink including no alkyl polyol having a boiling point of 280 degrees C. of higher under 1 atmospheric pressure, a drying process of drying the white image to a drying ratio of to 80 percent, and a second recording process of recording a colored image on the white image with a drying ratio of 40 to 80 percent by an inkjet method using a colored ink having a surface tension of 30 mN/m or lower, including a coloring material, and including no alkyl polyol having a boiling point of 280 degrees C. or higher under 1 atmospheric pressure.
In this technology, the white ink and the colored ink make an ink set including no alkyl polyol having a boiling point of 280 degrees C. or higher, thereby shortening the drying time of both inks. However, to achieve the drying ratio of 40 to 80 percent, it is required to set a long drying time.
As described above, such a limited selection of an organic solvent having a relatively low boiling point in ink is known as a measure to increase the drying speed. However, blurring of printed matter is not sufficiently suppressed.